Stents are used in a wide variety of locations in the body including in coronary arteries, renal arteries, peripheral arteries including iliac arteries, arteries of the neck and cerebral arteries. Stents are also used in other bodily locations including but not limited to arteries, veins, biliary ducts, urethras, fallopian tubes, bronchial tubes, the trachea, the esophagus and the prostate.
Stents typically are self-expanding, balloon expandable or a hybrid of the two. Self-expanding stents may be made of shape memory metals such as nitinol, shape memory polymer materials, or constructed of non-shape memory metals but of a design which exhibits self-expansion characteristics. Balloon expandable stents are typically delivered on a balloon and the balloon is used to the expand the stent. Hybrid stents have both self-expanding properties and balloon expanding properties.
Typically, stents are delivered to desired bodily locations via the use of catheters. A catheter comprising a stent is introduced into a bodily vessel and advanced through the vasculature in the body until the stent is positioned in a desired location. Usually, the stent will be protected by a retractable sheath which is disposed about the stent and which increases the profile of the delivery catheter. The sheath may be removed from about the stent via the use of a retraction device such as a pull-wire, pull rod or a catheter tube which is connected to the sheath. As part of the removal, the sheath may optionally be rolled off of the stent. In the case of self-expanding stents, the sheath may also restrain the stent from self-expanding. Once at the desired location, the stent is either allowed to self-expand or is balloon expanded. In the case of self-expanding stents, the self-expansion may occur as a result of the removal of the sheath from about the stent.
Unfortunately, many self-expanding stent delivery systems, in particular those using retractable sheaths, employ cumbersome and/or bulky deployment mechanisms.
There remains a need for medical device delivery systems in general and stent delivery systems in particular which avoid the use of cumbersome and/or bulky deployment mechanisms.
There also is a need for expandable medical devices which are capable of being retained on a catheter with a retractable retaining member of minimal profile.
The entire content of all of the patents listed within the present patent application are incorporated herein by reference.
The invention in various of its embodiments is summarized below. Additional details of the invention and/or additional embodiments of the invention may be found in the Detailed Description of the Invention below. An abstract of one of the embodiments of the invention is also provided below.